Duplicating process



AISTE SGHAL IRQ, E l c t DUPLICATING ilAlll-tljl'tjl.

Ito Drawing.

Specification of Letters l atent.

Patented Dec" 2th Application filed May 21, 1919.

seamen manna THE raovrsions or run sea or Manes a, 1921, 4a srar.

To all whom it may concern-.-

Be it known that I, AIsIK SonArIno, a citizen of the independent State of Littauen, Russia, residing at Berlin, Stralauerstrasse 56, Germany, have invented certain new and useful Improvements in a Duplicating Process (for Which I have filed an applica tion in Germany, April 13, 1917), of Which the following is a specification.

My invention refers to a duplicating process and more especially to a method for printing fatty colors from colloid surfaces such as hectographic layers or sheets.

It is old to print fatty inks or colors from printing surfaces substantially consisting of glycerin and gelatin, the original being to this end Written with a tanning ink and pressed upon the colloid printing surface which is then inked with fatty colors. In proceeding in the manner described the. color shall not adhere to the printing surface itself,but only to the places Where tanning ink has been deposited. Experience has shown that it is not possible to obtain neat copies in this manner for the reason that the printing surface Will also take on the color more or less outside the places covered With ink. In order to obviate this drawback it has been proposed to add suitable substances to the mass constituting the printing surface or to subject the surface during the printing operation to a special treatment. i

I have now ascertained that no special treatment of the mass as a. whole or of the printing surface is required if in printing fatty colors a mass containing glycol is used as a printing medium, such mass being prepared either by adding glycol to the ordinary duplicating mass or by partly or entirely replacing the glycerin in the mass by glycol. Printing surfaces prepared after this manner and containing glycol Will not .take on any fatty ink or color and all danger of the copies becoming soiled is averted. lam aware that it is old to add glycol to the masses constituting duplicating layers, glycol being used at present as a substitute for glycerin. Up till now however duplicating layers or pr1nting surfaces containing glycol have not been used in the printing of fatty colors, it being unknown that the presence of glycol in the inassrenders it absolutely repellant for such colors.

The use of masses containing glycol in the printing of fatty colors offers the very importa-nt technical advantage of rendering all intermediate operation superfluous so that it is possible to constantly ink and print in immediatelsuccession. 'lhe copies obtained are of a very superior quality and free from all blotches. The new process further ofi'ers the advantage of allowing the printing surface Which had just been employed for printing fatty inks to be used immediately thereafter for making hectograp'hio copies. To this end the fatty color need merely be removed from the tanned places by covering the surface "With paper preferably printing paper. The taking of hectographic copies from a printing surface having been used for printing fatty colors is not possible With duplicating masses such as used up till now and necessitating an intermediate treatment with stern l. afix my signa 

